In the prior art, a portable generator comprises a generator set composed of an engine and a generator, and the generator set is placed inside a casing with a handle, so as to make it convenient for customers to carry and use outdoors. There are two kinds of structure for the portable generators currently available on the market: One is that the generator set is fixed inside one cover body, which is fixed and connected at the upper part and the lower part to the upper part and the bottom of the casing, respectively; the other is that the generator set is fixed inside the casing through a support. Although these two kinds of structure are good in soundproof effect, cooling effect and overall rigidity, they have such shortcomings as complicated structure, bothersome maintenance and increased weight, and especially violent vibration during usage.